Lungs of the Library
The double skin and double floor serve as air duct and heat buffer. The space between the skins creates a “solar motor” that breathes when exterior flaps are opened or closed. The mass of the concrete structure acts as a passive thermal funnel.
In lower temperatures the external flaps close. Using the chimney effect, fresh air is then drawn through an underground tunnel and up the thermal core of the building. In moderate temperatures the flaps open, allowing fresh and recirculated air to mix and be cooled by the core. According to Behling, for 60 percent of the year the library is ventilated by simply opening panels or using controlled fresh air drawn from below. The library consumes 35 percent less energy than a comparably sized building.
Outside air is transmitted through underground tunnels. Depending on the weather, the building is either heated or cooled by water pipes embedded in the concrete slab floor. On extremely hot days cooling is provided by air-conditioning in the existing buildings. “The best machine is one that you don’t have to switch on,” Behling says. “Most of the year the building operates completely with its own natural ventilation.”
The structural yellow space frame, by German company MERO-TSK supports the membrane and helps create column-free space. “When you look through some openings in the skin, you can see the yellow structure, which I thought would be more interesting and cheerful,” Behling says.